Rolling mill



y 6, 1952 H. J. WALLACE 2,595,910

ROLLING MILL Filed Nov. 19, 1945 3 Sheets-Sheet 1 11209725071 //[/VP)/ JW444465,

3 Sheets-Sheet 2 May 6, 1952 H. J. WALLACE ROLLING MILL Filed Nov. 19,1945 May 6, 1952 WALLACE 2,595,910

ROLLING MILL Filed Nov. 19, 1945 3 Sheets-Sheet 3 Patented May 6, 1952ROLLING MILL Henry J. Wallace, Scarsdale, N. Y., assignor to United.StatesSteel Company, a corporation of- New Jersey Application November19, 1945, Serial No. 629,519

2 Claims. 1

This invention relates to a rolling mill and more particularly to such amill for removing eccentricity from seamless tubing. The manufacture ofseamless tubes is such that the wall thickness throughout the peripheryof the tube varies and it is impossible to completely eliminate thiseccentricity by any mill or method now in use. This residualeccentricity results in a tube which does not have maximum strength forits weight.

Other disadvantages of the eccentricity in tubes is well known to thoseskilled in the art and it is therefore a problem which many haveattempted to solve without success.

It is an object of my invention to provide a rolling mill which willremove eccentricity from seamless tubes.

Another object is to provide a method of removing eccentricity fromseamless tubing.

These and other objects, will be more apparent after referring to thefOIIOWiIlg specification and attached drawings, in which:

Figure 1 is an elevation of part of the rolling mill;

Figure 1 is an elevation of. the remaining part, the entire mill beingshown by uniting Figures 1 and 1 along line a.a

Figure 2 is an enlarged view of the rolls with a tube in position forworking;

Figure 3 is a sectional view taken along the line IIIIII of Figure 2;

Figure 4 is a sectional view taken on the line IVIV of Figure 2; and

Figure 5 is a sectional view taken on the line V-V of Figure 2.

Referring more particularly tov the. drawings, the reference numeral 2indicates the bed of a lathe on which the mill is mounted. At one end ofthe bed 2 is a motor 4 which, through suitable earing 6, rotates themandrel 8-over which the workpiece T passes. The mandrel is made insections, section in being removable to allow the finished tube to beremoved from the mandrel. Such mandrels are commonso that the detailsthereof need not be set forth here. The forward end of the mandrelcarries. the internal working rolls 12 in a manner whichwilllee-explained hereinafter. Surrounding the outer periphery of the tube Tand cooperating with the rolls [2 are the outer working rolls I4 whichare mounted in a rotatable housing [6 as will be explained in detaillater. The housing i6 is rotated from the motor I8 through suitablegearing 20. A tube support 22 for supporting the tube T is mounted onthe inlet side of the rolls l2 and I4 and a tube clamp 24 is arranged onthe exit side to prevent 2, rotation of the finished tube. The end ofthe tube is supported by an internal gripper 26 which is carried by thecarriage 28 which is moved on the slide 33 by means of a hydraulic motor32. The clamp 24 is mounted on a carriage 34 which is moved to thedesired position on guide 3t by means of a hydraulic motor 38. The motor38 is connected to the carriage 34 by means of' a tension rod 40 on eachside of the head, the rods 46 being connected by cross bars 42. As bestshown in Figure 2, the mandrel 8 has a reduced portion 44. at itsforward end. The first part of this reduced portion is cylindricallyshaped as shown at 46 and merges into a conical portion 48. The extremeouter portion. 50 is further reduced in diameter and threaded to receivethe nut 52 which holds a roller cage 54in place on the reduced portion44. The inner portion of the roller cage is shaped in the same manner asportion 44 and the outer surface is substantially parallel to the innersurface. The cage 54 is provided with a plurality of openings56 whichextend along the conical portion thereof and merges into openings 58 inthe cylindrical portion thereof. Rollers 60 and 62 are received-inalternate openings 56, roller 60 being somewhat longer than roller 62.Rollers 64and 66 are received in openings 58. Rollers 64 whicharesomewhat shorter than rollers 66, abut against rollers 60 whilerollers66 abut against rollers 62. The rollers 69, 62, 64 and 66 bearagainst. the mandrel surface 44 which forces them against the outerspherical portion of the openings 56 and 5-3 to hold them in place. The.housing I6 is counterbored to receive the'roller cage. 68, thecounterbore having a cylindrical surface 10 merging into a conicalsurface. The cage 68 has three openings 14 around its periphery toreceive the rollers 16. The cylindrical portion of cage 68 has openings78 which are in line with openings 14 and which contain rollers 80.. Thecage 68' also has openings 82 for receiving rollers 84 which aresomewhat longer than rollers 80-. The cage is held in place by means ofa retaining member 86, which is fastened to housing 16 by means of capscrews 88.

The operation of the device is as follows:

A guide piece 90, which is machined to the uniform wall thicknessdesired in the finished tube, is placed over the mandrel 8 and betweenthe inner and outer rolls in order to center the inner rolls withrespect to the outer rolls. A tube T, which may be either hot or cold,is gripped internally by the gripper 26 and fed to the rolls bysupplying pressure fluid to hydraulic motor 32.

In a particular example, the outer rollers are driven in a clockwisedirection, as shown in Figures 3, 4 and 5, at a speed of 150 R. P. M.and the mandrel is rotated in a counterclockwise direction at a speed of150 R. P. M. As the tube passes through the rolls it is expanded in theconical portion of the pass and finished to the desired concentric shapein the cylindrical portion. If three or more rolls are mounted on themandrel in the expanding part of the roll pass, the expanding action ofthe rolls will put the wall of the tub in tension circumferentially, butnot to such an extent so as to cause the metal to flow. While intension, that portion of the tube being worked, which is in excess ofthe theoretical minimum of the unprocessed tube, is subjected toadditional rolling action. The combination of these forces causes themetal to flow circumferentially at the heavy wall and not at the lightwall as would be th case from expanding action only. With the speed setforth and with the number of rollers shown, there Will be 4350 swagingimpacts per minute on the tube. The finished tube as it leaves the rollsforces the guide piece 90 therefrom over the mandrel and thereafter thecentering of the inner rolls with respect to the outer rolls isaccomplished by means of the finished tube. The inner and outer rollsare peripherally skewed in opposite direction in order to feed thefinished tube from the rolls. After the tube T passes entirely throughthe rolls, section In of mandrel '8 is separated from the rest of themandrel and the tube removed therefrom. It will be understood that thenumber of rolls may be varied and that they need not be skewed.

While one embodiment of my invention has been shown and described, itwill be apparent that other adaptations and modifications may be madewithout departing from th scope of the following claims.

I claim:

1. A rolling mill for removing eccentricity from a tube comprising arotary mandrel, a set of short rolls mounted around the periphery ofsaid mandrel with their axes arranged in a substantially conicalpattern, a set of long rolls mounted around the periphery of saidmandrel adjacent said first set of rolls with their axis arranged in asubstantially cylindrical pattern, a rotary housing surrounding saidmandrel, a set of short rolls mounted in said housing and surroundingthe first set of short rolls with their axes inclined in the samegeneral direction as the first set to form a conical pass at the feedend of said rolling mill, a second set of long rolls mounted in saidhousing and surrounding the first set of long mandrel rolls with theiraxes substantially parallel to the axes thereof to form a substantiallycylindrical pass at the exit end of said rolling mill, means for feedinga tube to the rolls, means for rotating the housing in one direction,and means for rotating the mandrel in the direction opposite to thehousing, said cylindrical portion of said roll pass being adapted toreceive a tubular guide piece having the uniform wall thickness desiredin the finished tube to thereby center the rolls on the mandrel withrespect to the rolls in the housin at the beginning of the rollingoperation, the end of the finished tube forcing the guide piece from theroll pass with the finished portion of the tube thereafter keeping themandrel centered, said cylindrical portion of the pass being of suchgreater length than said conical portion that the area of the finishedtube in the cylindrical portion will resist the transverse force appliedby the rolling operation in th conical pass caused by the eccentricityof the workpiece.

2. A rolling mill for removing eccentricity from a tube comprising arotary mandrel, a set of short rolls mounted around the periphery ofsaid mandrel with their axes arranged in a substantially conicalpattern, a set of long rolls mounted around the periphery of saidmandrel adjacent said first set of rolls with their axes arranged in asubstantially cylindrical pattern, a rotary housing surrounding saidmandrel, a set of short rolls mounted in said housing and surroundingthe first set of short rolls with their axes inclined in th same generaldirection as the first set to form a conical pass at the feed end ofsaid rolling mill, a second set of long rolls mounted in said housingand surrounding the first set of long mandrel rolls with their axessubstantially parallel to the axes thereof to form a substantiallycylindrical pass at the exit end of said rolling mill, means for feedinga tube to the rolls, means for rotating the housing in one direction,and means for rotating the mandrel in the direction opposite to thehousing, said cylindrical portion of said roll pass being adapted toreceive a tubular guide piece having th uniform wall thickness desiredin the finished tube to thereby center the rolls on the mandrel withrespect to the rolls in the housing at the beginning of the rollingoperation, the end of the finished tube forcing the guide piece from theroll pass with the finished portion of the tube thereafter keeping themandrel centered, the number of rolls and the length thereof in saidcylindrical portion of the pass having such greater tube engaging areathan the rolls of said conical portion that the area of the finishedtube in the cylindrical portion will resist the transverse force appliedby the rolling operation in the conical pass caused by the eccentricityof the workpiece and thereby maintain the mandrel centered.

HENRY J. WALLACE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

